I've also seen a adapters that take VGA or S-Video and convert it to RCA/Composite Video however the reviews on those devices arent always the most promising. I'd suggest you play with some searches on Newegg.
Its a nice thing to have once you have it. As Ive mentioned before I sometimes hook up my somewhat broken laptop to my LCD TV through VGA. I like it. But if your going to use an HDTV and get a new video card you might want to look into getting a vid card with HDMI. This desktop Im on has an HD card in it but I don't have an LCD in this room to try it out so Ill have to take this thing over to that TV one of these days.